The 21st century may never top this and it's only 2015.

[Jimmy Higgins]

How reusable are the rockets? They must be under a bunch of stress when in use.

And we are boned, if this is the best we can do this century.

 

[Bronzeage]

How reusable are the rockets? They must be under a bunch of stress when in use.

And we are boned, if this is the best we can do this century.

Elon Musk and his engineers are checking that out now. The reality of exploration, from the time of Leif Ericsson and since, has been the expense. It's a gamble with very poor odds. A tremendous amount of resource must be devoted to the pursuit.


The reason I say this may never be topped is because of the significance of reducing the resources required for space flight. The rest is just another magic trick.

 

[fromderinside]

Elon Musk and his engineers are checking that out now. The reality of exploration, from the time of Leif Ericsson and since, has been the expense. It's a gamble with very poor odds. A tremendous amount of resource must be devoted to the pursuit.

The reason I say this may never be topped is because of the significance of reducing the resources required for space flight. The rest is just another magic trick.

So why isn't anyone working on building a high vacuum tunnel for launch. Yes it would be expensive, very expensive, but there's a multi-billion dollar CERN particle collider sin't there? Apparently no one here at this esteemed forum has the whatever to tackle the problem even conceptually.

We just don't seem to have risk takers any more. I mean how is a bareback national leader riding a horse bareback deemed a wow?

 

[Bronzeage]

Elon Musk and his engineers are checking that out now. The reality of exploration, from the time of Leif Ericsson and since, has been the expense. It's a gamble with very poor odds. A tremendous amount of resource must be devoted to the pursuit.

The reason I say this may never be topped is because of the significance of reducing the resources required for space flight. The rest is just another magic trick.

So why isn't anyone working on building a high vacuum tunnel for launch. Yes it would be expensive, very expensive, but there's a multi-billion dollar CERN particle collider sin't there? Apparently no one here at this esteemed forum has the whatever to tackle the problem even conceptually.

We just don't seem to have risk takers any more. I mean how is a bareback national leader riding a horse bareback deemed a wow?

The competition of new technology is always the old technology. We have a system which works. We know how much it costs and have a good idea of the risks. All if this is balanced against a very uncertain return on investment. Any plan which starts off with, "Yes it would be expensive, very expensive," is already handicapped.

As for the horse thing, I get any of that.

 

[fromderinside]

So why isn't anyone working on building a high vacuum tunnel for launch. Yes it would be expensive, very expensive, but there's a multi-billion dollar CERN particle collider sin't there? Apparently no one here at this esteemed forum has the whatever to tackle the problem even conceptually.

We just don't seem to have risk takers any more. I mean how is a bareback national leader riding a horse bareback deemed a wow?

The competition of new technology is always the old technology. We have a system which works. We know how much it costs and have a good idea of the risks. All if this is balanced against a very uncertain return on investment. Any plan which starts off with, "Yes it would be expensive, very expensive," is already handicapped.

As for the horse thing, I get any of that.

I once drew a cartoon of a cave man by a stream using bamboo and skins to build a shelter while he was surrounded by children which I presented to a bunch of round heads at an engineering conference.

The point then was men who got it were considered weird and relegated to amusing the young.

My boom line was thank heaven for children they are free to see great things.

We need to be in really good or really bad times to permit risk takers to do their things. I'm pretty convinced this was just some really good times. Too bad we're back to counting coins.

I wish software innovators weren't so wrapped around the idea of being disruptive. They're using someone else's language.

 

[bilby]

Elon Musk and his engineers are checking that out now. The reality of exploration, from the time of Leif Ericsson and since, has been the expense. It's a gamble with very poor odds. A tremendous amount of resource must be devoted to the pursuit.

The reason I say this may never be topped is because of the significance of reducing the resources required for space flight. The rest is just another magic trick.

So why isn't anyone working on building a high vacuum tunnel for launch. Yes it would be expensive, very expensive, but there's a multi-billion dollar CERN particle collider sin't there? Apparently no one here at this esteemed forum has the whatever to tackle the problem even conceptually.

We just don't seem to have risk takers any more. I mean how is a bareback national leader riding a horse bareback deemed a wow?

Nobody is building a high vacuum tunnel because it really wouldn't help much, even if it could be done cheaply (which it can't).

Space isn't difficult to get to because it is a long way away; or because there's a lot of atmosphere in the way. There's more air in the way of a flight from Brisbane to the Gold Coast; or from Wilmington, DE to Baltimore, MD; or from Sacramento to San Francisco than there is in the way of a flight from Cape Canaveral to the ISS (or Cape Canaveral to the Moon; or Cape Canaveral to Mars, for that matter).

Space is hard to get to because you need to go FAST. Air resistance is not a significant problem for that objective; the atmosphere gets thin fast, and so much of the acceleration of a space launch occurs in a pretty good vacuum already.

Taking risks is one thing. Tackling the wrong problem because you don't grasp the basic physics is not risk taking though; it's wasting money, time, and effort. That's why nobody is dumb enough to seriously attempt it.

As Randall Monroe points out at the link above:

Space is about 100 kilometers away. That's far away—I wouldn't want to climb a ladder to get there—but it isn't that far away. If you're in Sacramento, Seattle, Canberra, Kolkata, Hyderabad, Phnom Penh, Cairo, Beijing, central Japan, central Sri Lanka, or Portland, space is closer than the sea.

Getting to space is easy. It's not, like, something you could do in your car, but it's not a huge challenge. You could get a person to space with a small sounding rocket the size of a telephone pole. The X-15 aircraft reached space just by going fast and then steering up.

But getting to space is easy. The problem is staying there.

 

[GenesisNemesis]

In 2100 we'll likely be much closer to sustainable fusion, or have it, so there's that at least.

 

[bigfield]

There's no real reason the atmosphere could prevent a ground based projectile from achieving orbit. It is just another obstacle to be overcome. Air resistance is a factor with rockets as well. Also, one could imagine a hybrid system, where the railgun takes the place of the first rocket stage, or something.

As long as the astronauts don't mind their brains being forced out through their assholes.

 

[fromderinside]

Nobody is building a high vacuum tunnel because it really wouldn't help much, even if it could be done cheaply (which it can't).

Space isn't difficult to get to because it is a long way away; or because there's a lot of atmosphere in the way. There's more air in the way of a flight from Brisbane to the Gold Coast; or from Wilmington, DE to Baltimore, MD; or from Sacramento to San Francisco than there is in the way of a flight from Cape Canaveral to the ISS (or Cape Canaveral to the Moon; or Cape Canaveral to Mars, for that matter).

OK So worrying about metals and air resistence as speed impediments is relatively small potatoes technologically then? That's good.

Space is hard to get to because you need to go FAST. Air resistance is not a significant problem for that objective; the atmosphere gets thin fast, and so much of the acceleration of a space launch occurs in a pretty good vacuum already.

Taking risks is one thing. Tackling the wrong problem because you don't grasp the basic physics is not risk taking though; it's wasting money, time, and effort. That's why nobody is dumb enough to seriously attempt it.

Going fast cheaply, relative to building a new craft for every launch were the main reasons I suggested high vacuum environment and meglev propulsion. What is the trade between making and maintaining a high vacuum meglev system versus building and launching with great single time expenditures and fuel were the wish bones of my problem.

Hand wave is not characteristic bilby.

So we build a 400 billion dollar launch system that can be maintained for 100 billion for fifty years which can launch 100 craft per year. I think that stacks up against a 30 billion dollar launch site that costs 400 billion to maintain for 50 years launching 100 500 million dollar one offs (50 billion a year or 2.5 trillion). Besides technology modifications should be much less with a fixed launch system.

As for recovery put satellites in a much higher orbit so the craft can decelerate to near zero horizontal velocity by the beginning of atmosphere reentry. Saves on cost of materials and danger to occupants.

 

[bilby]

OK So worrying about metals and air resistence as speed impediments is relatively small potatoes technologically then? That's good.

Space is hard to get to because you need to go FAST. Air resistance is not a significant problem for that objective; the atmosphere gets thin fast, and so much of the acceleration of a space launch occurs in a pretty good vacuum already.

Taking risks is one thing. Tackling the wrong problem because you don't grasp the basic physics is not risk taking though; it's wasting money, time, and effort. That's why nobody is dumb enough to seriously attempt it.

Going fast cheaply, relative to building a new craft for every launch were the main reasons I suggested high vacuum environment and meglev propulsion. What is the trade between making and maintaining a high vacuum meglev system versus building and launching with great single time expenditures and fuel were the wish bones of my problem.

Hand wave is not characteristic bilby.

So we build a 400 billion dollar launch system that can be maintained for 100 billion for fifty years which can launch 100 craft per year. I think that stacks up against a 30 billion dollar launch site that costs 400 billion to maintain for 50 years launching 100 500 million dollar one offs (50 billion a year or 2.5 trillion). Besides technology modifications should be much less with a fixed launch system.

As for recovery put satellites in a much higher orbit so the craft can decelerate to near zero horizontal velocity by the beginning of atmosphere reentry. Saves on cost of materials and danger to occupants.

That is physically impossible - as explained in the link provided. The height of the orbit is determined by the horizontal velocity; in orbit, changing speed is THE SAME THING as changing height.

You are making it very clear that you don't grasp the fundamental mechanics at play here; You are therefore not able to contribute meaningfully to the discussion until you learn them.

 

[fromderinside]

As for recovery put satellites in a much higher orbit so the craft can decelerate to near zero horizontal velocity by the beginning of atmosphere reentry. Saves on cost of materials and danger to occupants.

That is physically impossible - as explained in the link provided. The height of the orbit is determined by the horizontal velocity; in orbit, changing speed is THE SAME THING as changing height.

You are making it very clear that you don't grasp the fundamental mechanics at play here; You are therefore not able to contribute meaningfully to the discussion until you learn them.

Yeah, yeah ballistic reentry. You're not trying. One could expend a great amount of energy to quickly reduce speed of the craft after which it would just fall into the earth with relatively low thermal effects.

A solar powered meg lev system sustained in orbit by some sort of solar wind drive system could provide the power and platform necessary to bring the spacecraft to low relative speed after which it could use something similar to Rutan's wing used in suborbital flight but useful for return from orbit if velocities are reduced to control reentry.

 

[bilby]

That is physically impossible - as explained in the link provided. The height of the orbit is determined by the horizontal velocity; in orbit, changing speed is THE SAME THING as changing height.

You are making it very clear that you don't grasp the fundamental mechanics at play here; You are therefore not able to contribute meaningfully to the discussion until you learn them.

Yeah, yeah ballistic reentry. You're not trying. One could expend a great amount of energy to quickly reduce speed of the craft after which it would just fall into the earth with relatively low thermal effects.

No, one could not.

A solar powered meg lev system sustained in orbit by some sort of solar wind drive system could provide the power and platform necessary to bring the spacecraft to low relative speed after which it could use something similar to Rutan's wing used in suborbital flight but useful for return from orbit if velocities are reduced to control reentry.

No, it could not.

 

[barbos]

I am not sure what are you trying to achieve here. Recovering satellites would cost more than they are worth.
The only thing one could possibly be interested in is removing old satellites from space but that is expensive and practically impossible for high orbits.

 

[Loren Pechtel]

OK So worrying about metals and air resistence as speed impediments is relatively small potatoes technologically then? That's good.



Going fast cheaply, relative to building a new craft for every launch were the main reasons I suggested high vacuum environment and meglev propulsion. What is the trade between making and maintaining a high vacuum meglev system versus building and launching with great single time expenditures and fuel were the wish bones of my problem.

Hand wave is not characteristic bilby.

So we build a 400 billion dollar launch system that can be maintained for 100 billion for fifty years which can launch 100 craft per year. I think that stacks up against a 30 billion dollar launch site that costs 400 billion to maintain for 50 years launching 100 500 million dollar one offs (50 billion a year or 2.5 trillion). Besides technology modifications should be much less with a fixed launch system.

As for recovery put satellites in a much higher orbit so the craft can decelerate to near zero horizontal velocity by the beginning of atmosphere reentry. Saves on cost of materials and danger to occupants.

That is physically impossible - as explained in the link provided. The height of the orbit is determined by the horizontal velocity; in orbit, changing speed is THE SAME THING as changing height.

You are making it very clear that you don't grasp the fundamental mechanics at play here; You are therefore not able to contribute meaningfully to the discussion until you learn them.

The Steam sale is over but can I recommend trying Kerbel Space Program anyway? The physics model isn't perfect by any means but it does handle orbital mechanics with reasonable fidelity. (Although it breaks down when it comes to the interaction of multiple bodies.) Beware that the learning curve is brutal. One of the tutorial missions has me stumped so far! (I understand how to accomplish the objectives but I'm running out of fuel.)

 

[James Brown]

My son plays the Kerbel Space Program, and it looks fun. I'd play it myself, but then long ago I realized that I can have:

A) A family

B) A career

C) An active gaming life

And that I have to pick two.

 

[fromderinside]

Yeah, yeah ballistic reentry. You're not trying. One could expend a great amount of energy to quickly reduce speed of the craft after which it would just fall into the earth with relatively low thermal effects.

No, one could not.

Sure one can. Just provide an energy source in space with sufficient energy to decelerate lifted mass to zero or say about 1000-1500 mph horizontal by the time it reached significant atmosphere. Plenty of power available in space with which to power deceleration if one can apply it to the ship. Large array of solar cells and storage devises could provide enough power to supply a maglev assembly to bring the spacecraft to normal materials (titanium and the like) down, to say 1500 mph horizontal, to earth, I also presume maglev could also be used to put a craft into orbit (the high vacuum long length tunnel maglev rail system).

I suspect such a launch system would need to insert the vehicle at about 10000 feet to avoid most of the atmosphere thereby minimizing additional G forces and velocity loss after vehicle enters atmosphere at end of tunnel.

Maybe a competent one could calculate the distance one would have to accelerate the vehicle at a 3 G rate to achieve escape velocity plus safety factor for drag after ship leaves tunnel and maglev propeller. Intuitively it seems pretty rational.

I saw this on the Kerbal space program site. Next-Generation launch technologies achievable with CURRENT technology http://forum.kerbalspaceprogram.com...hnologies-achievable-with-current-technology/

First of all, magnetic launch-assist systems: because REAL drag falls off exponentially at hypersonic speeds, and there's no reason we can't launch our rockets at Mach 26 (Mach 25 is orbital velocity) out the end of basically a hyper-powered Maglev in a vacuum tube (note that the tube exits at the TOP of a mountain, where the air is thinner)

That the technology exists doesn't mean it's practical. A SpaceTram would have to be launched out of a mountain at least 7km high. AFAIK, those only exist in the himalayas. Most certainly not in Europe. Try getting a mega-engineering project to work in the highly politically unstable himalayas. On top of that, the tube must be at least a 100 km in length, unless one utilizes truly extreme acceleration rates (which will then soupify any normal space probe designs).

Mach 26 is a speed, not an acceleration. To reach escape velocity (7.5 km/s, Mach 25.5), 12 minutes of acceleration at 1G will be enough. However, for that acceleration, you need a tube of 52,000 km to reach escape velocity. Since that's larger than the circumference of Earth, that's unpractical. For greater acceleration you need an ever smaller tube. At 5G, you need "only" 2250km. At 15G you need just 250km, and at 25G you only need 90km. Perhaps one can shorten the route further by applying short ms bursts of super acceleration (~100G) at intervals.

Note: a human usable system would only be about 1500 miles long.

 

[barbos]

magnetic levitation in space? what the fuck is that?

 

[fast]

Then chemical propellants not being powerful enough is the unwon challenge that redirected us from the path of (solving the other problems that would have arisen had we sought to perfect single stage rocket design) to the path of (solving the other problems that did arise as we sought to perfect the multi stage design). So, we're not on the path we would have preferred, as we would have preferred to have been on the original path. It's nice that we're solving the problems that we come across on this path, but it's going to be nicer once we solve the original unwon challenge and get back on the path it would have been nice to never have had the need to diverge from. Then, we can get to solving the future problems that will arise on that more preferred path.

That path being to find a way to economically lift mass out of Earth's gravitational well. With our current technology that is with chemical rockets and dropping empty fuel tanks (multi-stage) along the way to reduce the mass being lifted is the most economical. This doesn't mean we have given up on alternatives. Materials science may soon give us a material that has enough tensile strength and low enough mass that we can construct a space elevator to lift our payloads our of Earth's gravity well on a cable, one end moored on Earth and the other end moored to a synchronous satellite. We can then forget about rockets except for those constructed in orbit to travel to other planets and moons in the solar system.

I keep coming back to that sentence. There's something about it that keeps bugging me. Let's disregard the economical qualification since it doesn't speak to our technological abilities.

Quick question: no hidden point, just a question regarding Earth's escape velocity. Is that a necessity based on a technological deficiency?

 

[Loren Pechtel]

That is physically impossible - as explained in the link provided. The height of the orbit is determined by the horizontal velocity; in orbit, changing speed is THE SAME THING as changing height.

You are making it very clear that you don't grasp the fundamental mechanics at play here; You are therefore not able to contribute meaningfully to the discussion until you learn them.

Yeah, yeah ballistic reentry. You're not trying. One could expend a great amount of energy to quickly reduce speed of the craft after which it would just fall into the earth with relatively low thermal effects.

A solar powered meg lev system sustained in orbit by some sort of solar wind drive system could provide the power and platform necessary to bring the spacecraft to low relative speed after which it could use something similar to Rutan's wing used in suborbital flight but useful for return from orbit if velocities are reduced to control reentry.

And you don't get it--we have a much better understanding of the energies involved.

You expend more than 90% of the rocket getting it into orbit. If you want to stop it you must expend another 90% of the rocket to do so.

 

[skepticalbip]

That path being to find a way to economically lift mass out of Earth's gravitational well. With our current technology that is with chemical rockets and dropping empty fuel tanks (multi-stage) along the way to reduce the mass being lifted is the most economical. This doesn't mean we have given up on alternatives. Materials science may soon give us a material that has enough tensile strength and low enough mass that we can construct a space elevator to lift our payloads our of Earth's gravity well on a cable, one end moored on Earth and the other end moored to a synchronous satellite. We can then forget about rockets except for those constructed in orbit to travel to other planets and moons in the solar system.

I keep coming back to that sentence. There's something about it that keeps bugging me. Let's disregard the economical qualification since it doesn't speak to our technological abilities.

Quick question: no hidden point, just a question regarding Earth's escape velocity. Is that a necessity based on a technological deficiency?

I'm afraid that I don't understand the question. Escape velocity is a matter of physical law - it doesn't have anything to do with putting stuff in Earth orbit. Escape velocity is the velocity that something would have to leave the surface of the Earth (assuming that there was no atmosphere and assuming a simple two body problem) for it not to be pulled back by gravity. Something leaving at approx. 25,000 MPH which is Earth's escape velocity (again assuming no atmosphere and a two body problem) would continually be slowed by Earth's gravity reaching zero velocity (with respect to Earth) at infinity.

Putting something in orbit is a different problem. It doesn't matter how slowly something is lifted out of the atmosphere but for it to put in and remain in low Earth orbit (not fall back to Earth) it will have to be accelerated to almost 18,000 MPH tangential to the Earth's surface.

I hope that addresses you question.